Ibuprofen is an arylpropionic acid derivative with the IUPAC name 2- 4-isobutylphenyl propanoic acid. To design a retrosynthesis pathway for the synthesis of ibuprofen from starting materials with no more than 6 carbons, we can break down the molecule into simpler precursors. Here's a possible retrosynthesis pathway:1. Disconnection of the carboxylic acid group COOH from the ibuprofen molecule: Target molecule: Ibuprofen 2- 4-isobutylphenyl propanoic acid Retrosynthetic step: 2- 4-isobutylphenyl propanal + CO22. Disconnection of the isobutyl group from the 4-isobutylphenyl moiety: Target molecule: 2- 4-isobutylphenyl propanal Retrosynthetic step: 4-Isobutylbenzaldehyde + Propionaldehyde3. Disconnection of the benzene ring from the 4-isobutylbenzaldehyde: Target molecule: 4-Isobutylbenzaldehyde Retrosynthetic step: Benzaldehyde + IsobutyleneStarting materials:1. Benzaldehyde C7H6O 2. Isobutylene C4H8 3. Propionaldehyde C3H6O 4. CO2 Carbon dioxide Synthesis pathway:1. Friedel-Crafts alkylation of benzaldehyde with isobutylene to form 4-isobutylbenzaldehyde.2. Wittig reaction between 4-isobutylbenzaldehyde and propionaldehyde to form 2- 4-isobutylphenyl propanal.3. Arndt-Eistert homologation of 2- 4-isobutylphenyl propanal to form ibuprofen 2- 4-isobutylphenyl propanoic acid .This retrosynthesis pathway provides a route to synthesize ibuprofen from starting materials with no more than 6 carbons.